Hemolytic disease of the newborn may occur against antigen incompatibilities. Studies to identify women at high risk of hemolytic disease in the newborn will be sought by screening their sera for the presence of cytotoxic antibodies against the combined Lewis and blood group determinants which represent the terminal pentasaccharides of Type I blood group antigenic molecules. A curriculum for the Program of Asthma Care Training for Children was developed and tested in pilot groups. A randomized clinical trial has been initiated which will involve about 100 children to determine the effect of this Program. Pilot trials proved very promising. It should be advantageous in helping asthmatic children in terms of minimizing absence from school and increasing ease of disease management. Human B lymphoid cell populations have been divided into three subgroups on the basis of antibody class and response time following antigen challenge in subjects with immune deficiencies. In patients with normal immunoglobulin levels but low levels of specific antibodies, the low specific antibody response was found to be due to specific B cell deficits or increased suppression by T cells, indicating that a variety of disorders may produce this syndrome. Infections, especially pneumonias, are a major public problem in patients with immune deficiencies. A trial of pneumococcal vaccine is underway in an attempt to reduce susceptibility to klebsiella pneumoniae and, possibly, other pulmonary infections of patients receiving bone marrow transplants.